How to set the fully qualified domain name(FQDN) in ubuntu?

Edit /etc/hostname and add your unqualified hostname:
Edit /etc/hosts:
sudo vi /etc/hosts
Add an entry of your desired hostname by replacing boson where is the fully qualified hostname and boson is hostname. boson
Test your configuration by opening a terminal and enter the below commands:
  • hostname
    • This should output boson
  • hostname -f
    • This should output


Changing the Hostname (RedHat)

RedHat based system use the file /etc/sysconfig/network to read the saved hostname at system boot. This is set using the init script /etc/rc.d/rc.sysinit






So in order to preserve your change on system reboot edit this file and enter the appropriate name using the HOSTNAME variable.


To temporarily change the hostname on a RHEL server (changes will revert back to what is in /etc/sysconfig/network after reboot):


hostname <hostname-here>


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